Handbook of Optical Sensors

462

Handbook of Optical Sensors

EM eld would result in macroscopic polarization that is proportional to the external

electric eld E, P =

ε

0

χE. e parameter χ is a material status–dependent quantity char-

acterizing the collective response; the value χ possesses a randomly uctuating por-

tion associated with Δε(t,z). is uctuating dielectric parameter Δε gives a uctuating

polarization-induced light emission in all directions as cartooned in Figure 16.2. Some

of the scattered Rayleigh lights are recaptured by the waveguide, and they were sent

in the backward direction. is backward propagating Rayleigh scattered light has a

time delay that ca ...